I. Field of the Invention
Embodiments of the present invention relate generally to the field of advanced wound therapy involving the use of localized therapeutic fluid delivery to damaged and healing tissues and in specific embodiments, dressings optimized for use with mobile continuous diffusion of oxygen therapy systems.
II. Background and Description of Related Art
Damaged tissue, including skin and soft tissue wounds, triggers an increase in demand for oxygen. Oxygen has been reported to increase fibroblast migration and replication (Knighton, et al.), increase the rate of collagen production and tensile strength of collagen fibers (Hunt, et al.), stimulate angiogenesis (Knighton, et al.), promote macrophage chemotaxis (Bosco, et al.), and enhance the antibacterial activities of leukocytes, including phagocytic function (Hohn et al.), thereby increasing the removal of cell debris and promoting physiological wound debrisment.
There are two ways in which damaged moist tissues can get oxygen: (1) it can be absorbed through the lungs and carried through the cardiovascular/respiratory system to the wound site; or (2) oxygen may be supplied to the wound directly, either by contact with oxygen in ambient air (at a concentration of about 21%) or by pure oxygen (100%), delivered by an external oxygen source and administration apparatus designed for this purpose. In both cases, oxygen reaches the cells of such damaged tissue by diffusion, which is relevant for the skin and soft tissue wounds to which embodiments of the present disclosure are directed.
In many patients, for example patients with venous stasis ulcers, diabetic foot ulcers, some pressure ulcers and other wounds, normal delivery of oxygen via the cardiovascular/respiratory system is compromised. While there may be sufficient blood supply to a local area to maintain normal physiological processes, including the maintenance of dermal and epidermal tissues, the oxygen capable of being supplied to a local area in patients with compromised vascularity is often insufficient to supply oxygen at the greater amounts needed to fuel cellular processes for repair of damaged tissues, even when advanced wound care modalities such as vacuum-assisted closure techniques are used. The occlusive dressings used with this and some other wound closure methodologies can restrict access of these hypoxic tissues to oxygen which may otherwise diffuse into a moist wound from the ambient air, decreasing the likelihood of wound closure in those clinical situations in which adequate flow to and from the tissues cannot be restored.
Advanced wound care treatments such as Topical Oxygen Therapy (TOT), also known as Topical Hyperbaric Oxygen Therapy (THOT), deliver pure oxygen to wounds, but because these systems are not portable, and their use immobilizes the patient. Treatment time with these systems is therefore typically limited to about 90 minutes per day. As the cells in a healing wound have continuous need for oxygen, the limited duration of therapy practically possible with these modalities may limit their clinical utility.